New technologies help increase agricultural efficiency

On the first day of FAPESP Week Nebraska-Texas, researchers from Brazil and the United States present studies focused on making agricultural production more sustainable

By Karina Toledo, in Lincoln | Agência FAPESP – It is estimated that by the year 2050, the world’s population will increase 30%. During this same period, according to projections from the Food and Agriculture Organization (FAO) of the United Nations, meat consumption will increase nearly 73% while the consumption of dairy products will increase 58%.

Conversely, the amount of arable land will increase only 5% and agricultural producers will have to deal with the challenges brought by climate change and increasingly stringent environmental regulations.

In the assessment of Professor Fábio Marin, of the Luiz de Queiroz College of Agriculture (ESALQ) of the University of São Paulo (USP), in Brazil, efficiency gains in agriculture are the only way to ensure food security for the future of the world’s population and at the same time, protect natural ecosystems.

The topic was the highlight of Monday morning (9/18) on the schedule of the FAPESP Week Nebraska-Texas symposium, whose objective is to promote collaboration among scientists from Brazil and the United States. The event, which will run from September 18-22, was organized by FAPESP in partnership with the University of Nebraska – Lincoln and Texas Tech University.

“The key word is intensification [of agriculture]. We need to produce more, but the increase in production has to come from gains in productivity and not from expanding the amount of cultivated area. And agricultural modeling is a fundamental tool for this,” Marin said.

Marin presented several FAPESP-funded projects developed at ESALQ during his talk. Among them is a model that allows for the quantification of sugarcane production efficiency in various regions of Brazil. The tool, described this year in the Agronomy Journal, also allows scientists to calculate the maximum productivity that can be achieved in each area.

“The model was based on an experiment we conducted over a period of five years in Piracicaba, São Paulo State, and one year in Petrolina, Pernambuco State. What we did was grow sugarcane in optimal conditions for its development. And we observed how several physiological processes occurred in these optimal conditions, including photosynthesis and root growth. All the data were put into the model so that it would be able to simulate sugarcane growth,” Marin explained to Agência FAPESP.

With the help of the tool, researchers from ESALQ put together a map of potential productivity of the various regions in Brazil where sugarcane is grown. Next, they compared the results to actual productivity data measured by the Brazilian Institute of Geography and Statistics (IBGE).

“We concluded that our sugarcane production efficiency is only 50%. In other words, we’re producing half of what would be possible under optimal conditions,” the researcher explained.

According to Marin, if 100% efficiency were achieved, it would be possible to meet 2024 demand for sugarcane estimated by the Ministry of Agriculture, Livestock, and Food Supply and still reduce the cultivated area. However, if things remain the way they are, more than 2 million hectares of sugarcane will be needed to meet Brazil’s future demands.

Irrigation efficiency

Because agriculture is the economic activity that most consumes water in the world, and this raw material, essential to human life is becoming increasingly scarce, efficiency gains in the agricultural sector must necessarily involve new irrigation technologies.

The topic was discussed in a talk by Christopher Neale, director of the Water for Food Institute at the University of Nebraska. His group has worked to develop variable rate irrigation systems, in other words, technologies able to “prescribe” the ideal amount to be sprayed on crops, taking into account soil differences and climate factors such as rain, air humidity, solar radiation and wind.

“In a typical field, soil is not uniform. There are patches that vary in terms of their capacity to retain water – their infiltration capacity. We need to pay attention to these factors because excess water can cause erosion,” Neale said.

According to the researcher, variable irrigation systems allow making the best use of rainwater, since they do not allow the soil to become saturated.

“Let’s suppose rain is forecast for three days from now, but the crop needs to be irrigated immediately so that it does not suffer from crop stress. We can lightly irrigate so that when the rain comes, the field can take advantage of that water,” he explained.

According to Neale, variable rate irrigation technology is already available in the United States, especially in Nebraska where agriculture represents a significant part of the economy. However, the cost is still high and farmers are not convinced of its benefits.

“We’re currently conducting studies to measure these benefits in particular. We are looking to assess how much water consumption is reduced by and, consequently, how much energy is utilized in the pumping. That amount will diminish soil erosion and leaching, a process by which fertilizers are carried away to below the area where the nutrients can be absorbed by the roots – which can contaminate the aquifers,” he explained.

According to Neale, the state of Nebraska has a total of 3.4 million irrigated hectares – most of which consists of corn and soybean fields. The number is nearly that of Brazil’s total irrigated areas, which measure 5.5 million hectares.

New technologies to increase irrigation efficiency was also the subject of a talk by Fernando Braz Tangerino Hernandez, a professor at the School of Engineering (FEIS) of the State University of São Paulo (Unesp) in Ilha Solteira.

His group has developed a method to estimate water loss in the field through a process called evapotranspiration, which includes both transpiration from plant leaves as well as soil evaporation.

“We are using data from eight weather stations in northwest São Paulo State to estimate the transfer of water into the air and thus do a large-scale calculation of how much needs to be replaced,” he explained.

The stations measure factors such as temperature, wind speed and direction, air humidity and solar radiation. These data are updated every five minutes on the internet.

Using a software called SMAI (Irrigated Crop System Management), available for free download, it is possible to calculate the irrigation necessary (more information available at:clima.feis.unesp.br).

The development of drought monitoring technologies and the establishment of public policies to mitigate its impact were the topic of the lecture by Mark Svoboda, Director of the National Drought Mitigation Center at the University of Nebraska-Lincoln.

“Our goal is to produce information that is useful and at the same time, capable of being applied in the field. We work with farmers to try to understand their needs,” Svoboda said.